. >> rockets crisscross the sky as israel bombards the gaza strip. militants are firing back. a decision about a ground invasion could come any time. here's the latest. reporter: on this fourth day of fighting, israel lairched hundreds of rockets into georgia sacks pounding landmarkssmarks d centers of power, including the ministry building and a vast groundwork of underground tunnels. militants there undaunted, unleashing 600 rockets against the jewish state, specialry in the south where the damage is extensive. as attacks on testify avive and jerusalem mark the first time hamas has been able to fire rockets. >> hamas fire a rocket at jerusalem. throughout the city in arab neighborhoods and jewish neighborhoods. reporter: israel's iron dome defense system proving particularly effective as in this attack on tel aviv, intercepting a significant proportion of incoming rockets. at least three israelis and 40 palestinians have been killed, men civilians. across the city, residents live in fear of israeli air strikes. this man says, all night we were worried whether they will shell